Round die for wood turning lathes



y 1954 A. E. GINGRAS 2,678,069

ROUND DIE FOR WOOD TURNING LATHES Filed Sept. 14, 1950 JNVENTOR. A? 7.4 0? E. G/lVG/PAS zim,

Arroemsy Patented May 11, 1954 UNITEDSVTATES PATENT OFFICE Application September 14, 1950, Serial No. 184,861 2 Claims. (Cl- 142- 50) This invention relates to new and improved constructions for the round dies which are used mainly in back knife gauge lathes but which are found to be applicable in other relations.

The prior art round die in this type of machine is made smaller in diameter than the rough work as turned down by the roughing gouge, and in the operation thereof as the Work passes through, causes scorching, burning, and smoking, often resulting in rejected pieces and effecting injury to the operator of the lathe, both through the smoke and the scorching and burning of the operators hands or person.

It is the principal object of the present invention to provide a device of the class described which overcomes the objections described above and other detriments found in the conventional round die; the provision of a round die steady rest which while holding the work exactly in relation to the V-knife and back knife, still does not smoke, scorch, etc; the provision of a device as above described including a round die which fits the work being produced by the roughing gouge, and supports the work without smoking and includes a new and improved element which presses against the work in cooperation with the round die so as to cut down the overly-tight engagement between the work and the die in the prior art, While still holding the work in the exact position required and avoiding the detrimental results in the prior art described above.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which Fig. 1 is a view in elevation of a back knife gauge lathe to the round die of which the present invention is applicable;

Fig. 2 is a view in elevtaion of a round die with the new attachment therefor in section; and

Fig. 3 is a view in front elevation of the device of Fig. 2 looking in the direction of arrow 3 in Fig. 2, part being in section,

In Fig. 1 there is shown a generally conventional back knife gauge lathe having a base H), a bed l2, a head stock M, a tail stock 16, a back knife IS, a carriage 2B fed by a screw 22 and generally traveling to the left in Fig. 1, on the working stroke. The work is shown at W and, of course, rotates at high speed while the carriage moves to the left.

Carriage 20 carries a roughing gouge 24, a round die 26 which is the subject of the present invention. and a v-knife.

In the operation of these machines, the roughing cutter 24 turns the work from square to round and then it passes through the round die 26 wherein it must be very firmly held. As the work is thus held it is rough shaped by the V-knife 28 and then finish cut by a formed (back knife) cutter [B which descends as the carriage moves to the left. It is. the round die which causes the trouble explained above.

As shown in Figs. 2 and 3, the round die 26 comprises a block provided with a round hole 30 made with a diameter slightly in excess of that of the work W so that the latter may pass easily therethrough without the scorching and charring ordinarily anticipated. In order, however, to hold the work firmly in the block there is provided a. plunger 32 mounted in a housing 34. This housing is at one side of the block and extends laterally thereof, and the plunger in the housing is projected or expressed to the left by a spring 36 adjustalbly located by a plug 38 and locked in position by a nut 40. The plunger has a concave nose 4| forming a curved work-engaging surface generally fitting the work and co-extensive with and on the radius of the hole surface. The inner end of the housing 34 adjacent the hole has the same shape, as shown at 43.

The plunger, as clearly shown in Fig. 2 exerts a pressure on the work and holds it in the round hole 30 and in so doing, clearly maintains the work tightly guided and on a fixed axis. It has been found that this construction holds the work just as firmly as in the prior art dies but completely avoids all burning and charring, particularly since the work rotates at a high speed.

The plunger 32 is limited to a very small motion by means of a screw 42 working in a hole 44 in housing 34. Whereas the plunger therefore has a small amount of movement, it is strictly limited so that no attention is needed when a new piece of work enters the round die and yet slight variations in the work are accounted for. The angularity indicated in Fig. 3 at 46 is occasioned by the operation of the conventional sash and knife bar holding the finishing cutter l8 and forms no part of the present invention. The housing 34 could be bolted to the round die 26 but it is preferred that it be cast integral therewith.

It will be seen that this invention provides a round die block steady rest having a work-receiving hole of a diameter larger than the work in combination with a curved end spring-pressed plunger which carries out all the objects of the invention and avoids the serious difficulties encountered in prior art machines. The present invention not only provides for faster and better production with less chatter and rejects, but also preserves the health of the machine operator by failing to burn his hands and to blind and shock by reason of the smoke inevitably present under operation of machines of the prior art.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but-what I claim is:

1. A die block for a back knife gauge lathe comprising a block having a hole therethrough of a slightly larger diameter than that of the anticipated workpiece, a housing to one side of and extending laterally of said block, a spring-pressed plunger within said housing andnormally pressing the workpiece against the interior surface of said hole opposite to theplunger, theirmerend of the housing adjacent to the hole and theinner end of the plunger having curved work-engaging 4 7 surfaces of substantially the same radius as that of the hole, whereby the work is securely held to an exact line of advance through the die.

2. The die block of claim 1 including means limiting the extent of the plunger in a direction toward the work.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 245,233 "Sillman Aug. 2, 1881 285,115 Conkey Sept. 18, 1883 301,185 Tyler July 1, 1884 562,271 -Blum f June 16, 1896 1,360,787 Pennoyer Nov. 30, 1920 1,674,317 ="Bufi June 19, 1928 .,1,729,111 :Hoogerhyde Sept. 24, 1929 2,434,661 Krueger Jan. 20, 1948 

